MD Settings: Display > Overscan: Update text and fix focus

chrome/browser/resources/settings/device_page/display_overscan_dialog.js

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 /**
  * @fileoverview
  * 'settings-display-overscan-dialog' is the dialog for display overscan
  * adjustments.
  */
 
@@ skipping 14 matching lines @@
 
   /**
    * Keyboard event handler for overscan adjustments.
    * @type {?function(!Event)}
    * @private
    */
   keyHandler_: null,
 
   open: function() {
     this.keyHandler_ = this.handleKeyEvent_.bind(this);
-    this.addEventListener('keydown', this.keyHandler_);
+    // We need to attach the event listener to |window|, not |this| so that
+    // changing focus does not prevent key events from occuring.
+    window.addEventListener('keydown', this.keyHandler_);
     this.comitted_ = false;
     this.$.dialog.showModal();
+    // Don't focus 'reset' by default. 'Tab' will focus 'OK'.
+    this.$$('#reset').blur();
   },
 
   close: function() {
-    this.removeEventListener('keydown', this.keyHandler_);
+    window.removeEventListener('keydown', this.keyHandler_);
 
     this.displayId = '';  // Will trigger displayIdChanged_.
 
     if (this.$.dialog.open)
       this.$.dialog.close();
   },
 
   /** @private */
   displayIdChanged_: function(newValue, oldValue) {
     if (oldValue && !this.comitted_) {
@@ skipping 83 matching lines @@
     /** @type {!chrome.system.display.Insets} */ var delta = {
       left: x,
       top: y,
       right: x,
       bottom: y,
     };
     settings.display.systemDisplayApi.overscanCalibrationAdjust(
         this.displayId, delta);
   }
 });